Does commercial increase of seed for use in restoration result in selection for genotypes that are not representative of wild populations?

Due to increasing interest in grassland restoration, today’s fragmented landscapes often cannot supply enough seed to support restoration plantings. Thus, restorations often use seeds that are available in large quantities from seed production fields. Native species that are cultivated for seed propagation may experience both intentional and unintentional selection. Under certain conditions, this could increase plant performance, but alternatively, cultivars may not be well adapted to the environment of restoration sites, where conditions may be more extreme than in propagation fields. Additionally, many of the commercially available seeds may lack local adaptation in the region where they are planted. To investigate the implications of seed propagation for Midwestern prairie restoration, we established a series of common gardens on sand and loam soil types in Michigan, in which we grew cultivated and wild collected genotypes of two prairie grasses, Andropogon gerardii (big bluestem) and Schizacyrium scoparium (little bluestem). Cultivated genotypes were larger and often had greater fecundity in the first year than wild collected genotypes. However, we also found evidence that wild collected genotypes may be better adapted to sandy soils. In A. gerardii, cultivated genotypes had significantly fewer inflorescences on sand than on loam, whereas Michigan remnant populations did not show any difference. The greater initial growth and fecundity of commercially available genotypes could allow better establishment, particularly on loam soils. The effects of cultivation are likely to gain greater importance due to interest in prairie grasses as a source for biofuels, which would introduce more cultivars onto the landscape.